This proposal requests partial support for an intensive two-week laboratory and lecture course for advanced graduate students, postdoctoral fellows and independent investigators that focuses on the development and genetics of zebrafish, with special emphasis on nervous system development and function. In its 18th year, this course is still the only one of its kind worldwide, covering time-proven and newly-developed technologies, geared towards their applications in zebrafish. Mornings and afternoons are devoted to mostly laboratory exercises punctuated with relevant round-table discussions, while the evenings are spent in data evaluation, lectures by leading figures in the zebrafish international community, and discussions. During the first part of the course the students learn techniques that are standard to any zebrafish laboratory: microscopy, sperm cryopreservation, in vitro fertilization, injection of RNA, CRISPR/Cas9, and antisense morpholinos, whole-mount RNA in situ hybridization and immunohistochemistry, and specimen mounting and imaging. A second focus of the first week is zebrafish genetics, with interactive round-table discussions on genome editing, disease modeling, and web-based genomics resources. The second week of the course focuses on zebrafish nervous system development and function, although many of the techniques employed are also applicable to studying the development and function of other organ systems. Participants are introduced to general anatomy through adult dissection and to neuro- anatomy; they then learn a variety of techniques for labeling and transplanting cells that are used to assess cell fate and cell behavior. One emphasis is on high-resolution live imaging using various types of microscopes and fluorescent markers. The final days of the course teach techniques for studying visual, motor and social behaviors, at the level of both genes and neural circuits. Throughout the two week course, interspersed with the laboratory sessions are round-table sessions that teach the practical side of zebrafish research (e.g., husbandry, constructing and maintaining a zebrafish facility) and discuss latest developments in the field (e.g. disease modeling and genome editing). Finally, each of the ~20 course faculty presents a 1-hour evening seminar centered on their current research oriented towards the laboratory sessions. These highly interactive seminars are considered by participants to be a highlight of the course, as they frequently nucleate hour-long scientific discussions into the evening about outstanding biological questions. The MBL Zebrafish Course is carefully crafted to provide to excellent scientists who are newcomers to the field training in key zebrafish techniques and interactions with leading figures in zebrafish research. In addition, as most faculty stay for the full durationof the course, it also creates a fruitful ground for networking and developing outstanding collaborations.